Waves are one way in which energy may be transferred between stores. Both mechanical and electromagnetic waves will transfer energy but not matter.

Waves may be transverse or longitudinal. Electromagnetic waves are transverse waves with a wide range of properties and uses. Sound waves are longitudinal waves.

All waves will reflect and refract in the right circumstances. The reflection and refraction of light explains how people see images, colour and even optical illusions.

The amount of infrared radiation absorbed or radiated by a surface depends on the nature of that surface. The Earth’s temperature also depends on the rates at which light and infrared radiation are absorbed by the Earth’s surface and atmosphere.

Understanding how to approach exam questions helps to boost exam performance. Questions will include multiple choice, descriptions and explanations, using mathematical skills, and extended writing.